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 Post subject: GDI and dirty valves?
PostPosted: August 13, 2016, 11:45 pm 
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A friend and I were talking last night about our trucks. He has the ecoboost 6 cyl and I have the V8.

He said that he bet that I had lower maintenance costs than him and better gas mileage. He then launched into and explanation about the valves getting dirty quickly on direct injection and then went on to say he was only getting 16 mpg.

He had to leave and because of our schedules we won't get to talk for another couple of weeks. So how bad is this dirty valve issue? I knew it existed but since he has only had his truck for about 3 months I never dreamed it would be something he would have to deal with.

And yes he is getting worse mileage than I get with the V8.

He said that the 2017 Fords would have a combo fuel injection system just to eliminate this problem. Part would be injected directly and part on the valves. I've not heard anything about this kind of change up nor have I heard enough about the dirty valve issue to think it would warrant that kind of change up.

And while this isn't directly about Locosts, once we begin to be able to put these engines in our cars it will become one.

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PostPosted: August 14, 2016, 11:10 am 
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I ran into this issue a little while ago while looking at used cars. The Mazdaspeed6 has the same issue. They get carbon buildup on the intake valves from the EGR, but with direct injection there's no fuel to wash it away so it accumulates rather quickly. I highly doubt it would happen in 3 months, I think it's more of a 30-50k mile sort of thing. The Lexus IS250 also suffers from this problem, but the Lexus IS350 does not since it has both direct and port injection.


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PostPosted: August 14, 2016, 11:11 am 
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The dirty valve issue exists on all direct injected motors.
The gack from the PCV accumulates on the port and back of the valve.
The only fix at this time is walnut shell blasting at 50k intervals.

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PostPosted: August 14, 2016, 12:31 pm 
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I was reading about the PCV valve addition to the crud and a catch can seems to be the solution to that part of the problem.

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PostPosted: August 15, 2016, 2:56 am 
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As with many engine concerns, regularly performing an 'Italian tune-up' can help. :drive:

Regarding fuel economy, reports I have seen put most of the self-proclaimed 'EcoBoost' engines (aside from the 1.0) as more boost and less eco. But talk about good marketing.

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PostPosted: August 15, 2016, 8:01 am 
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How do Diesels avoid the problem? Don't they have PCV valves?

Bill


Last edited by BBlue on August 15, 2016, 8:36 pm, edited 1 time in total.

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PostPosted: August 15, 2016, 9:38 am 
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I think the Turbo engine and economy is highly dependent on how you drive them. Some people will get better gas mileage some will not. I know a fleet owner that is very happy with his new Turbo F150's.


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PostPosted: August 15, 2016, 9:52 am 
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I've driven the 6 cylinder ecoboost truck and it felt almost exactly like my V8 and since it's rated a few more mpg than mine when it's time to replace mine (2017) that's where I thought I'd be heading.

It didn't make sense to me that he was having carbon build up issues so soon after owning his truck. If I do get one of these engines I guess I'll be adding a catch can almost instantly which apparently is what everyone needs to do who uses a direct injection engine in a Locost.

I've seen multiple Sea Foam type products in the stores to use on these engines. Maybe that becomes a standard thing to do a couple of weekends a year.

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PostPosted: August 15, 2016, 10:27 am 
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carguy123 wrote:
...I've seen multiple Sea Foam type products in the stores to use on these engines. Maybe that becomes a standard thing to do a couple of weekends a year.

That can only clean what it contacts - which isn't the backside of the intake valves.

I guess I'll be the exception here and say that I haven't had any problem with my F150 ecoboost. Averages 19 mpg in mixed driving (22 freeway) and at 60k miles, is still running fine.

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PostPosted: August 15, 2016, 10:51 am 
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If you put it in the intake then it does contact the back side of the valves.

I'm glad to hear you like yours and aren't having any unusual probs. You're getting almost exactly what mpg I get on my V8, or rather did get for over 100,000 miles.

I changed tires and instantly dropped 2 mpg.

I'd rather hoped to break 20 in around town driving in the new truck.

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PostPosted: August 21, 2016, 6:34 pm 
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When I worked for a Hyundai dealer we saw that a lot, and we used BG 271 & 272 on a closed pair of intake valves. AFAIK, you can do 2 cyl and then 2 cyl, but yes the intake has to come off. Fairly big job for a DIY. Chemical is still better than walnut shells, IMO.

I changed to Mazda 20 months ago (huge mistake- company has a death wish- worst national management and product planning on the market bar none) and we don't have problems with build up. Not entirely sure why.


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PostPosted: April 10, 2017, 3:13 am 
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the pcv system leaves an oil residue on the intake and the egr system sends a bit of exhaust into the intake, then the particles and other crud from the exhaust stick into the oil residue. they bake at engine temp while constantly applying new layers. both these systems help emissions and mileage so the cpu is sure to keep a close eye on them. at minimum you can see if there is a way to do a pcv or egr delete by disabling the system and tricking or reprogramming the cpu to not notice it. oil from the pcv system is what you want to get rid of. an oil catch can that actually seperates the oil vapors from the crankcase would slow or stop it. or an external vacuum pump could be used to get the vacuum in the crankcase while not sucking oil vapor into the intake, doing this should stop buildup without hurting mileage. whatever you do needs to not piss off the cpu, and this is also most easily done with the pcv system.

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